Therapy for Gaucher's disease depends upon broad clinical and basic scientific knowledge of the disorder. Patients have been extensively studied and complications identified. Research on glucocerebrosidase addresses the biochemistry, cell biology, and molecular genetics of the enzyme. A clinical trial directed along the lines of pharmacodynamic assessment of mannose-terminated human placental glucocerebrosidase is underway. Results obtained in this study will form the basis of an efficacy investigation in Gaucher patients with this enzyme that is targeted to lipid storing cells.